Motion-picture apparatus of the optical compensating type



L. W. M GINTY MOTION-PICTURE APPARATUS OF THE OPTICAL COMPENSATING TYPESept 20, 1949.

2 Sheets-Sheet 1 Filed April 9, 1946 a S Q QN IN V EN TOR.

LUT/V f/P W We 67/1 7/ Sept. 20, 1949. L. w. McGlNTY 2,482,197

MOTION-PICTURE APPARATUS OF THE OPTICAL COMPENSATING TYPE V Filed April9, 1946 2 Sheets-Sheet 2 INVENTOR, Law/5A W W0 V/vrr Patented Sept. 20,1949 IMOTION-JPICTURE APPKRATUS OF THE lDPTICAL .GOMPENSATING Luther W.M'cGiiity,Chattanooga,"1enn,, assign- 'or *to -Leventhal Patents, 1110.,Chattanooga,

Tenn., a corporation of. Delaware Application April 9, 194e,:v Serialmissasis This linventionrelates lto.motion picture appasratusand moreespe'clallyto projectors in which :the film. moves .uninterrupte'dlyacross the optical axis and the .screenimagesare rendered stationaryJoyoptical compensation.

Them-pending application'ofLJacob F. Leven- .thal, S.eria1 .No. 656,196,.filed .March #22. I946, .now-Patent N0..2,440,-776,'issued.MayJ4, 1948,disclosesamotionpicture .projectorin which an optical compensatorproducestwo successive spaced virtuaLimages of a .fllm picture while itis being advanced:uninterruptedly across the optical: axis incombination with optical means includinga .movable optical 'unit forreimaging said virtual .images as areal .images in-.registering..relation .at the-screen :plane. .An-tobject of -.thisinvention .is .mechanism foraefiectingiactuation of said optical limitin timed'relation to the advancement .ofssaid ,iilm.

' Other .objects ,1 novel ieatureseand advantages of thisinvention"willibecomezapparent fromthe fol-- lowing: specification;and-accompanying drawings, wherein:

'Fig. 1is adiagrammatic section'inz'the direction or filmxtravet ofatzproi eotor=emboiiying .theinvenition;

Fig. 2 is 'a .planview :of ssuchs'a'pparatus Fig- .3 *israrear-elevation of a"porti'oni0f such sapp'aratuswith certain partsdnone-'positionfand Fig.4 is a viewtsimil'ar ItocFig.I3iwith1saidpartsinranother-iposltion.

l'A sourcesof light Hlrhas a :condenser lens .ll :a'ssociatedtherewithto direct light from "the source mtthroughthe'tfilm gateiztz.:-A sprocket l 3 co-operates with a retaining roller [4 to drawita -fllmF5 across the igate "l2. I' An coptieal mompensator I Bisrotatably'mountedjust' beyond the fihn v gate inposition'to' interruptthe lightzbeam passingirom the lensJ I through the film gate. Ihecompensatori l:6v is mountedwonra' shaft! lTto :whi-ch isattache'd apinion lj8 m'eshing with-.-a-'gear"l=3 "fixed to the shaftifl "by'whichthe sprocket-wheel l3 issupported. 'The*'pinion=l8 and the gear 9are in :isuch ratio that a *singie pictureEi'rame =crosses=ithe opticalaxis of .tthe proiector "'roree'ach complete revolutionzof the:compensator 5 ;-?there- "by forming -two-:-su -:c'essivespaced virtualimages V1 and V2 separated sin time from teach otherias disclosed inmeve'nthal 'Patent No. "2,067,771.

A stationary :obj'e'ctive lens :2 I :is provided trier producingzrealimages cifssuchavirtual iimrages and a: mirror T5 22 zis provi'ded iforefieetingireg'istry :o'f such'realaimages intheascreen"pianefi.:Theimirnor :2! iis oscillated i'bBtWGEII'JtWO positions, iin :one

Cage or one. ofthe virtualim'ages and in the other mflwhichit redirects.iightfor producing the real .image of =the-remaining virtual image.The. reflectorrlzisrigidiy fastenedtoashaftQZA prefer--ablyflihoughnot.necessarily, arranged in the. front 'focalplane.ofitheobjective 1ens.2 I. Means, later ttoibe described, .areprovidedfor effecting oscillation: of the mirror .22 -.between .the twopositions above mentioned. I

An obturator is provided for interrupting .the .light beam .twice,foneaeh completerevolution of the-compensator. t6.Thisobturator-consists. ofa pair of coaxial diametrically opposedarcuate sshields projecting fromone ifaceof .a plate .26

;-sup.ported by. a.- rotatable shaft 21 ,,parallel .to .the sshaftil.Theshields-25 are-rotatable aroundthe pobjectiveilens .12 l -.to .passalternately between the compensator and thelens l2l to interrupt the-fiow Of'ligh'b' from the lens-2 I- at such time as .the'compensator'lzi isiin positions'in whichthe pro- :duction of Wirtual:images -.is accompanied .by .undesirableeffects. -Rotationaof theobturator is efEected-throughthe medium of a gear :2 B on the shaft l1and a gear 29 on the shaftlkthese: gears -haVingm onesto-ohe.ratio.

:A lever 30 is I fixed towthe' shaft :24 and at one end-.is providedwithiapairaof arms 3 I converging aoutwardlystoiformwainotch 32. Theshaft-21cc- :centricallywsupportsithe inner race 33 of-a ball-bearingxhavmg its outer race 34 adapted to"entigagethearmsfll'withiclearance between one arm eand the-zouter racemember when 1 the other arm :engages the: outerfrace member. Rotation ofthe shaft 24*effectsimovementnof the periphery of the m5 fracemember -34toward and away 'from the arms 3| along a line perpendicular toralinej'oining-the axes df thevshaftsiuiand 21, therebycausingiosscillation-oftthedever :30 between the two posi-#tiOIiSiShOWIi in Figs. 53 andA by engagement of 40 :the outer race r34with-the arms -3l to oscillate the mirror 22. .The widtir of'thenotc'h32sissomewhat :greater than .the outeridiam'eter of therace mem- :ber:34so that theilever .30 :has two stationary .periods for each.completeirotation of the shaft 1 21.:Also,-the-.-convergence.of-thearms.3l is such "thatzazhalfwrevolutioneoi :thershait -.2 l .is required ioreefiectin.-.movement of the .-.lever 30 in .either direction-between itstwoextreme; positions. The lever 30 is provided withian arcuate surface35 .concentrimwith the. shaft 2.1 andalleaf-spring 36 bearseagainstsaidsurface. The spring 36 frictionally.opposestheoscillationotthe'lever 30. and zztends .to.retain. it-.-at rest.

ln-lthe separation. of the projector, the shaftds of whichitredirectsilightsior prodmingia'o'eal imtdrivenf.-at-.constant speed.byanysuitable means,

thereby causing one complete rotation of the compensator is duringpassage of one film picture across the optical axis of the projector andone complete rotation of the obturator to interrupt the light beam twicefor each complete rotation of the compensator 16. Each half revolutionof the shaft 21 causes movement of the lever 30 from one of its twopositions of rest to its other position of rest and the spring 35maintains the lever at rest during the period in which the outer race 34moves from contacting relation with one arm to contacting relation withthe other arm. The spring also serves to prevent movement of the lever30 under its own inertia after contacting relation of the outer race 34with an arm has been discontinued.

The clearance between the ball race 34 and the arms 3i is such that themirror 22 remains stationary except during the period that the obturatoris in position to interrupt the light beam. The timing is such that themirror is moved from one position to the other during the period thatthe obturator is interrupting the light beam and any vibration that maydevelop in the mirror is dissipated before the obturator has ceased tofunction. The mirror is completely detached from its driving mechanismduring the period of picture projection so that during this period it isabsolutely stationary.

I claim: 7

1. A device of the character described comprising a carrier movablebetween a first position and a second position, and a rotatableeccentric, said carrier being equipped with plane surfaces spaced aparta greater distance than the eccentric diameter and engageable by saideccentric periphery to effect movement of said carrier from its first toits second position during the initial portion only of a first halfrevolution of said eccentric and from its second to its 40 firstposition during the initial part only of the next half revolution ofsaid eccentric, and friction means opposing movement of said carrier ineither direction.

2. A device of the character described comprising a carrier movablebetween a first and a second position, means including a rotatableeccentric for applying force from the eccentric to the carrier duringthe initial portion only of a half revolution of said eccentric toadvance said carrier from its first to its second position and duringthe initial portion only of the successive half revolution of theeccentric to return said carrier from its second position to its firstposition, and friction means opposing movement of said carrier in eitherdirection.

3. A device or the character described comprising a carrier movablebetween a first and a second position, means including a rotatableeccentric for applying force from the eccentric to the carrier duringthe initial portion only of a half revolution of said eccentric toadvance said carrier from its first to its second position and duringthe initial portion only of the successive half revolution of theeccentric to return said carrier from its second position to its firstposition, and means for retaining the carrier stationary during theperiods when force is not applied thereto from the eccentric.

4. A device of the character described comprising means for feedingmotion picture film at uniform linear speed, a rotatable opticalcompensator, means to effect during movement of the film through asingle picture cycle rotation of the compensator through twocompensating cycles to produce two successive stationary spaced virtualimages of a luminous point on the film, optical means to reimage saidvirtual images in registering relation and including a 5 unit movablebetween a first and a second position, a rotatable eccentric, said unitbeing equipped with plane surfaces spaced apart at greater distancesthan the eccentric diameter and engageable by said eccentric peripheryto effect movement of said unit from its first to its second positionduring initial portion only of a first half revolution of said eccentricand from its second to its first position during the initial part onlyof the next half revolution of said eccentric.

5. A device of the character described comprising means for feedingmotion picture at uniform linear speed, a rotatable optical compensator,means to effect during movement of the film through a single picturecycle rotation of the compensator through two compensating cycles toproduce two successive stationary spaced virtual images of a luminouspoint on the film, optical means to reimage said virtual images inregistering relation and including a unit movable between a first and asecond position, said unit being equipped with plane surfaces spacedapart to form a gap, a member movable to and fro in said gap for lostmotion engagement with said surfaces to effect movement of said unit,and means for retaining said unit stationary during periods when forceis not applied thereto from said member.

6. A device of the character described comprising means for feedingpicture film at uniform linear speed, a rotatable optical compensator,means to efiect during movement of the film through a single picturecycle rotation of the compensator through two compensating cycles toproduce two successive stationary spaced virtual images of a luminouspoint on the film, optical means to reimage said virtual images inregistering relation and including a unit movable between a first and asecond position. and a ro- 5 tatable eccentric, said unit being equippedwith plane surfaces spaced apart a greater distance than the eccentricdiameter and engageable by said eccentric periphery to effect movementof said unit from its first to its second position 5 during the initialportion only of afirst half revolution of said eccentric and from itssecond to its first position during the initial portion only of the nexthalf revolution of said eccentric and friction means opposing movementof said unit.

'7. A device of the character described comprising means for feedingmotion picture film at uniform linear speed, a rotatable opticalcompensator, means to effect during movement of the w film through asingle picture cycle rotation of the compensator through twocompensating cycles to produce two successive stationary spaced virtualimages if a luminous point on the film, optical means to reimage saidvirtual images in 55 registering relation and including a unit movablebetween a first and a second position, means including a rotatableeccentric for applying force from the eccentric to the unit during theinitial portion only of a half revolution of said eccen- 7 tricpositively to advance said unit from its first to its second positionand during the initial portion only of the successive half revolution ofthe eccentric positively to return said unit from its second position toits first position, and friction 75 means opposing movement of saidunit.

8. A device of the character described comprising means for feedingmotion picture film at uniform linear speed, a rotatable opticalcompensator, means to effect during movement of the film through asingle picture cycle rotation of the compensator through twocompensating cycles to produce two successive stationary spaced virtualimages of a luminous point on the film, optical means to reimage saidvirtual images in registering relation and including a unit movablebetween a first and a second position, means including a rotatableeccentric for applying force from the eccentric to the unit during theinitial portion only of a half revolution of said eccentric positivelyto advance said unit from its first to its second position and duringthe initial portion only of the successive half revolution of theeccentric positively to return said unit from its second to its firstposition, and means for retaining the unit stationary during the periodswhen force is not applied thereto from the eccentric. LUTHER W. McGINTY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

